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American treasure hunters hit it big when they retrieved 60 tons of silver from the bottom of the Atlantic Ocean earlier this month.

Tampa, Fla.-based Odyssey Marine Exploration led the quest to find the underwater treasure, which sank in 1941 when the SS Gairsoppa — a British steamship that was secretly carrying silver from India to Great Britain to fund the war effort — was hit by a German U-boat torpedo.

Currently being held in a secret location in England, the valuable haul — paired with the group’s previous recovery of 48 tons of bricks of silver last year — is the largest precious metal recovery in history: It's worth an estimated $77 million.

“It’s starting to dawn on me now what we’ve achieved down here,” Odyssey’s senior project manager Andrew Craig told TODAY in a report that aired Tuesday.

The shipwreck was originally discovered in 2011, nearly 3 miles down off of Ireland’s coast. The team found much of the silver in the ship a year later, but only recently found much more on the ocean floor.

“The numbers are bit mind boggling,” Craig said. “I kind of just see (the silver) as very heavy lumps of weight that we've been flogging around for the last week.”

Kerry Sanders visits the secret location in England where $77 million worth of silver bricks are being held.Today

The silver bars, stacked on pallets shoulder high, began its journey from Colonial India to England in 1941.

A German U-Boat sank the 412-foot-long Gairsoppa steel-hulled cargo ship as it steamed off the coast of Ireland.

When it sank, the silver fortune was lost to the depths of the ocean until Odyssey began their search 10 years ago.

The archeologists used old shipping documents, war records and calculated drift to pinpoint the shipwreck.

Because it’s too deep to dive, salvage teams used Remotely Operated Vehicles, submarines with arms that can reach out and clutch to retrieve what is found.

The first ingot made it to the surface last year. The final bar, number 2792, was pulled from the wreck just last week.

Craig said finding the wreck never guaranteed finding the silver.

“We didn’t know where it was," he said. "It really was a case of going through every nook and cranny of the wreck site until we came across it.”

The majority of the silver, he said, was found in the mailroom.

Also retrieved from the sunken vessel: newspapers from 1941, financial documents and letters addressed with Indian postage.

Odyssey originally funded the $20 million exploration after winning a contract bid with the United Kingdom Department of Transportation. But, since the treasure was recovered, the British government is now responsible for footing the bill; Odyssey will retain 80 percent of the silver’s value, and the British government will inherit the rest.

"I don't think anyone ever expected to see it again,” said the transportation department’s Robert Cousins. “And here it is.”

The agency says it plans to send the silver to the Royal Mint — just in time to strike commemorative coins for the new prince.